@Andy Skinner I couldn't observe any issue with the new/existing logic app in UK South that I have tested at my end. Can you please confirm if you are still observing the issue.
If anyone is observing the same behaviour then please verify if there is any network extension/ad-on that might cause the issue loading the scripts. Test it in different browser/private mode/different network to see if it helps you.
If you still observe the same behaviour then please collect the F12 browser/network traces along with the screenshoot and portal session ID (ctrl + alt + D) for further analys the issue.